Regulatory mechanisms under investigation include: aspects of the regulation of gluconeogenesis and the inhibition of gluconeogenesis from lactate by histidine and histidine derivatives; glutamine and glutamate metabolism in the intestinal mucosa; the turnover of the 6-amino group of AMP in animal tissues, as measured by the rate of 15N incorporation; efforts of improving the metabolic competence of isolated hepatocytes and the isolated epithelium of the intestinal mucosa; the exchange of tissue ions with external medium in relation to the metabolism of hepatocytes; metabolic disturbances after trauma. BIBLIOGRAPHIC REERENCES: Interrelations between gluconeogenesis and urea synthesis. H.A. Krebs, P. Lund & M. Stubbs. In: Gluconeogenesis, p. 269 (Ed. R.W. Hanson & M.A. Mehlman) John Wiley & Sons Inc., 1976. The regulation of the degradation of methionine and of the one-carbon units derived from histidine, serine and glycine. H.A. Krebs & R. Hems. Advances in Enzyme Regulation 14, 493, 1976.